SCIENCE

Ancient Water, New Hopes in Search for Life
Scientists have discovered water that has been trapped in rock for more than a billion years. The water might contain microbes that evolved independently from the surface world, and it’s a finding that gives new hope to the search for life on other planets.

Discussion Ideas:

• The NPR article says Canada’s 1.5-billion-year-old water was trapped far beneath the Earth’s surface. It is fossil water, a type of groundwater that has been trapped underground for millions of years. Can students explain what groundwater is? Watch our “picture of practice” video “What is Groundwater” to see how one middle-school class approached the question.
  • Groundwater is freshwater located in soil or underground rock formations.
    • The most familiar form of groundwater is probably the liquid water trapped in aquifers. This is this form of groundwater the students and teacher in the video identify.
    • Groundwater also includes permafrost, a permanently frozen layer of soil.
    • Groundwater can be accessed by drilling wells. It can naturally flow to the surface through such features as geysers and springs.
• The ancient water was accidentally discovered by gold miners digging underground. Engineering projects—sewers or subways, for example—also require underground drilling. Why do students think gold miners, and not engineers or other underground workers, discovered the ancient water?
  • Gold miners drill much deeper than most engineering projects. In fact, these miners were drilling directly into the region’s bedrock, the hard, solid rock that underlies soil and sediment.
• Watch our video, “Exploring Alien Oceans,” with astrobiologist Kevin Hand, who is studying the possibilities for life on Jupiter’s moon Europa. At about 3:00 minutes into the video, Hand explains how astronomers and physicists identify a planet’s “habitable zone,” and where this zone may exist in our solar system. How do students think the discovery of Canada’s ancient water expands this definition of a “habitable zone”? Where do they think life could have developed in our solar system?
  • Both the “old Goldilocks” and Hand’s “new Goldilocks” scenarios depend on the presence of liquid water. The discovery of billion-year-old microbes in Canada’s fossil water suggests the possibility of microbial life hidden in the bedrock of planets or moons once thought “uninhabitable.”
    • The “old Goldilocks” scenario defined a planet’s habitable zone by its distance from a parent star. Too close, and a planet’s atmosphere would be far too hot to sustain life. Too distant, and the planet’s atmosphere would be far too cold. Earth, of course, is “just right.”
    • Hand’s “new Goldilocks” habitable zone is not entirely dependent on a planet’s distance from its parent star. A moon’s tidal interaction with its planet creates ample opportunity for geologic activity . . . and shifting, liquid oceans. Jupiter’s moon Io, for example, is the most volcanically active body in the solar system, while Hand thinks Europa‘s vast ocean may be dynamic enough to support microbial life.
    • Some astronomers think the ancient Canadian microbes hint at possibilities even closer to home. “As Mars got colder and drier,” the article says, “surface life would have died off. But Martian microbes might still survive deep in the planet’s crust—preserved in isolated pockets of water, just like the ones found in Canadian bedrock.”